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Pediatric Cardiology - Tetralogy of Fallot

​​​​​​​​​​​​​​​Tetralogy of Fallot (TOF) is a congenital heart defect (a child is born with it) and is a combination of several things:

  • Pulmonary stenosis - a narrowing of the pulmonary valve or area below the valve causing a blockage of bloodflow from the heart to the lungs.
  • Ventricular Septal Defect (VSD) - a hole in the dividing wall between the lower chambers of the heart (ventricles).
  • A thickened right ventricle.
  • An aorta that is shifted toward the right side of the heart causing it to sit over or "override" the ventricles above the ventricular septum.

Blood that should go to the lungs, goes instead through the hole in the heart wall and goes to the body without getting its supply of oxygen from the lungs. 

Tetralogy of Fallot may cause spells of blueness, labored breathing, and fainting and the child may tire and turn blue with exercise.

Marshfield Clinic has three full time pediatric cardiologists who are able to diagnose and treat any child with a congenital heart defect.


A child with TOF requires heart surgery to correct the heart defects. Surgery is generally done in the first year of life.

Cardiac Catheterization
In rare cases, a temporary procedure may be needed to increase blood flow to the lungs until a complete surgical repair can be done. 

A catheter is inserted into a blood vessel in the groin. With the help of live x-rays, the catheter is advanced up through the blood vessel until it reaches the heart. 

A tiny balloon at the end of the catheter is then inflated one or more times in the pulmonary valve, which opens the valve leaflets. Then the catheter and balloon are removed.

Through open heart surgery, the ventricular septal defect is repaired with stiches and a patch and the tissue causing obstruction at or below the pulmonary valve is removed as needed. In addition, the pulmonary artery may be enlarged.​​

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What Do You Know About Birth Defects?

See how much you know about birth defects. Learn what you can do to lower your risk.

1. How many babies in the U.S. are born with birth defects?
2. When is an unborn baby most at risk of developing a birth defect?
3. Which of these is a common birth defect?
4. Which of these habits of the mother-to-be can be harmful to the fetus?
5. A woman who is pregnant or considering pregnancy should get a health checkup. Which of these vaccines should be up to date before she gets pregnant because of the danger of the disease to the fetus?
6. Healthcare providers advise women to take 400 mcg of folic acid daily before they get pregnant and during pregnancy. What can this help prevent in the baby?
7. Pregnant women should not handle cat litter to lower the risk of becoming infected with which of these?
8. Which of these kinds of medicines can cause birth defects if taken when pregnant?
9. During prenatal care, a healthcare provider may recommend genetic screening tests for certain disorders. What is one thing that amniocentesis tests for?
10. Extra or missing chromosomes trigger genetic birth defects. What factor greatly increases the risk for an abnormal number of chromosomes in the fetus?